`cos e c(360^0)/7+cos e c(540^0)/7=` `cos e c(180^0)/7` (b) `cos e c(90^0)/7` `sec(180^0)/7` (d) `sec(90^0)/7`

The value of cos e c10^0+cos e c50^0-cos e c70^0 is ____

Which of the following is the greates? cos e c1 (b) cos e c2 cos e c4 (d) cos e c(-6)

sec^2(tan^(-1)2)+cos e c^2(cot^(-1)3) is equal to (a)5 (b) 13 (c) 15 (d) 6

Prove that (cos(90^0+theta)sec(-theta)"tan"(180^0-theta))/(sec(360^0-theta)sin(180^0+theta)cot(90^0-theta))=-1

cos20^0+cos80^0-sqrt(3)cos50^0 p. -1 cos0^0+cospi/7+cos(2pi)/7+cos(3pi)/7+cos(4pi)/7+cos(5pi)/7+cos(6pi)/7 q. -3/4 cos20^0+cos40^0+cos60^0-4cos10^0cos20^0cos30^0 r. 1 cos20^0cos100^0+cos100^0cos140^0-cos140^0cos200^0 s. 0

In A B C , prove that cos e c A/2+cos e c B/2+cos e c C/2geq6.

The value of cos e cpi/(18)-4sin(7pi)/(18) is

Find the value of cos(2pi)/7+cos(4pi)/7+cos(6pi)/7

If sec^(-1)x=cos e c^(-1)y , then find the value of cos^(-1)1/x+cos^(-1)1/ydot

The value of cos(pi/7)+cos((2pi)/7)+cos((3pi)/7)+cos((4pi)/7)+cos((5pi)/7)+cos((6pi)/7)+cos((7pi)/7) is 1 (b) -1 (c) 0 (d) none of these